Assiqnob



Sept 24, 1929. N, R. HMS 1,729,343

\ www BRUSH Filed Deo. l, 1924 6MM/TE Wirfamss i 50775/1260 @E5/H005 /MrER/AL.

gwwntoz @ttm Mg 4Patentedl Sept. 24, 1929 i /6 UNITED-'STATES PATENT OFFICE NELSON ROBERT HALS, OF DAYTON, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO DELOO-REMY CORPORATION, OF DAYTON, OHIO, CORPORATION 0F DELAWARE DYNAMO IBRUS Application tiled December 1, 1924. 'Serial No. 753,408.

This invention relates to brushes for dynamo electric machines and includes among its objects the provision of a brush having the required strength and hardness 5 which will not unduly wear the commntator during the life of the brush and which will not deposit particles upon the' commutator to any substantial extent.

Further objects and advantages of the present invention will be apparent from the following description of a preferred form thereof.

The brush is illustrated in the accompanying drawing.

16 The invention consists principally in combining with ra hite a substance'which will act as a binder and also as an abrasive. For this purpose what is known commercially as water glas has proved satisfactory as a 20 1n er an as an abrasive. Water glass is composed either of a silicate of sodium or otassium, or of a compound silicate ofy Both sodium or potassium, such silicate being y vknown to the trade as soluble.

Satisfactory results are obtained if the silicate is partly dehydrated so that .the steam eliminated during the moulding rocess will not be excessive, but there should e suicient water of crystallization to produce the necessary binding action.

The ingredients are mixed in the following pro ortions by weight:

85% to 96% graphite 15% to 4% soluble silicate 5 water glass. Thisproduct is entirely satisfactory for general purposes, but may be im roved by further heat treatment in a nonoxidizing atmosphere. A quantity of brushes which have been made by the' process just described are acked in carbonaceous material, such as 11e-black, within a covered metal box, and subjected to a temperature of 1700 F.

A still further improved product may be obtained by adding a quantity of powdered resinous material, such as bakelite moulding powder, to the mixture of graphite and silicate. These ingredients are moulded under heat and.pressure, as specified for moulding brushes of graphite and silicate alone and the moulded brushes are baked at about 17.00 F. in a nonoxidizin at os here in order to coke or smter the resinous material. Brushes made from a mixture of graphite, silicate and artificial resin by this process will be harder than brushes made by the same j process from a mixture of graphite and silicate alone, but the former brush will be more distorted in the final process of sintering the resin content, than the latter brush in which no resin was present in the mixture used to form the brush. This distortation is believed to be due to the liberation of gases from the resinous material in coking.

Besides bakelite, durite,

deIlStlOIl COmEOlll'l OI ElIeIlOl alla IllIIllIl e 11S@ l atisfactory results have been obtained with varying proportions of graphite, bakelite and sodium silicate, for example,- 85

86.7% graphite 8.2% akelite 5.1% sodium silicate 82 graphite 6 L 12 akelite 8 L 7 aphite kelite sodium silicate l 82 aphite j 8 gzlikelite 10 sodium silicate While the form of embodiment of the pres- .100

a henollc con- 804, I

$5- mately 350 F. and treatin in a nonoxi ent invention as herein disclosed, constitute preferred forms, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow. 5 What is claimed is as follows:

1. A dynamo brush including graphite, water glass and a non-abrasive moldable binder. l

2. A dynamo brush comprising graphite,

1 water glass and a sintered resinous material.

3. A dynamo brush com rising gra hite, water glass and a sintered p enolic con ensation product. A l

4. A dynamo brush comprising graphite,

15 water glass and sintered bakelite.

5. A dynamo brushcomprisin graphite and a binder including smtere resinous material and water glass, the proportions by weight of graphite being above 80%.

zo 6. A dynamo vbrush comprising raphite and a binder including sintered bake ite and water glass, the proportions4 by weight of sintered bakelite being from about 5 o 'to 10% and the proportions by weight o, graphite 25 being above 80%. A

7. The method of making a dynamo brush which consists in mixin graphite and a soluble silicate and moul g under heat and pressure.

$0 8. The method of making a d amo brush which comprises mixing grap vite with a binding material includlng a partly dehydrated soluble silicate in a dry state, and moulding under pressure and heat at aproxiizing atmos here at about 17 00 9. he method of making a dynamo brush which comfrises mixing graphlte, a partly dehydrate soluble silicate and an artificial 4o resinous material in a dry state, and moulding under pressure and heat at approximately 350 F. and treatin in a nonoxidizing atmosphere at about 1g00 F.

In testimony whereof I hereto aix my sig- 45 nature.

NELSON ROBER'I.` HAAS. 

